Highly Sensitive and Selective Detection of Pb(II) by NH2−SiO2/Ru(bpy)32+−UiO66 based Solid-state ECL Sensor

In this study, a novel electrochemiluminescence (ECL) sensor for highly sensitive and selective detection of Pb(II) was developed based on Ru(bpy) 3 2+ encapsulated UiO66 metal-organic-framework (Ru(bpy) 3 2+ −UiO66 MOF) and −NH 2 group functionalized silica (NH 2 −SiO 2 ). The NH 2 −SiO 2 with large surface area provided an excellent platform for the ECL sensor. As numerous exposed carboxyl groups were present on UiO66 backbone, the Ru(bpy) 3 2+ −UiO66 could be steadily immobilized to NH 2 −SiO 2 by forming amide bonds. Meanwhile, the introduced UiO66 MOF which used for the encapsulation of Ru(bpy) 3 2+ , significantly enhanced the ECL efficiency of the proposed sensor, as it possessed a large specific surface area and porosity for the loading of Ru(bpy) 3 2+ . Moreover, a high quenching effect on ECL intensity was obtained in the presence of Pb(II) in the electrolyte. Under the optimal conditions, the quenched ECL intensity showed a good linear relationship within Pb(II) concentration in the range from 1.0×10 −6 to 1.0×10 2 μM, with a detection limit of 1.0×10 −7 μM ( S / N =3). The proposed sensor for Pb(II) detection was simple in operation, rapid in testing, stable in signal, and showed a good anti-interference ability to some other metal ions. Besides, its application for detecting Pb(II) in a real sample was also investigated here. This work provides a potential platform for metal ions detection in environmental monitoring field.